News Release

Ra Pharmaceuticals to Present at the 22nd Congress of the European Hematology Association

CAMBRIDGE, Mass.--(BUSINESS WIRE)--May 18, 2017--
Ra
Pharmaceuticals, Inc. (NASDAQ:RARX), a clinical stage
biopharmaceutical company focusing on the development of next-generation
therapeutics for the treatment of complement-mediated diseases, today
announced that data on the Company’s first-in-class, oral small molecule
complement C5 program will be presented at the 22ndCongress
of the European Hematology Association (EHA) from June 22-25, 2017 in
Madrid, Spain. Inhibition of C5 is a clinically validated approach for
the control of complement-induced hemolysis in patients with paroxysmal
nocturnal hemoglobinuria (PNH).

Ra Pharmaceuticals is a clinical stage biopharmaceutical company
focusing on the development of next-generation therapeutics for
complement-mediated diseases. The Company discovers and develops
peptides and small
molecules to target key components of the complement cascade. For
more information, please visit: www.rapharma.com.

Forward-Looking Statement

This press release contains "forward-looking statements" within the
meaning of the Private Securities Litigation Reform Act of 1995,
including, but not limited to, statements regarding the safety, efficacy
and regulatory and clinical progress of our product candidates,
including RA101495. All such forward-looking statements are based on
management's current expectations of future events and are subject to a
number of risks and uncertainties that could cause actual results to
differ materially and adversely from those set forth in or implied by
such forward-looking statements. These risks and uncertainties include
the risks that Ra Pharma’s product candidates, including RA101495, will
not successfully be developed or commercialized; as well as the other
factors discussed in the “Risk Factors” section in Ra Pharma’s most
recently filed Annual Report on Form 10-K, as well as other risks
detailed in Ra Pharma’s subsequent filings with the Securities and
Exchange Commission. There can be no assurance that the actual results
or developments anticipated by Ra Pharma will be realized or, even if
substantially realized, that they will have the expected consequences
to, or effects on, Ra Pharma. All information in this press release is
as of the date of the release, and Ra Pharma undertakes no duty to
update this information unless required by law.